dStartDrawing must be called before using the drawing functions. dStartDrawing is used to define the element (Image control or Image variable) onto which the drawing functions will be applied.

For an Image control:

The drawing functions operate on a copy ("bitmap") of the image. You can use the drawing functions of Windows (via API or CallDLL32) but these Windows functions must use the DC (Device Context) returned by dStartDrawing.

dEndDrawing and dStartDrawing must not be called in the same process.The drawing will not be displayed if dEndDrawing and dStartDrawing are called in the same process: it will be automatically erased.

Related Examples:

Complete examples (WINDEV): WD Magnifier

[ + ] This example enables you to zoom part of the screen with a magnifier.The maximum zoom value is set to 8.Summary of the example supplied with WINDEV: The WLanguge function named dCopyBlt() and the WLanguage property named ..Opacity allow you to perform a capture of the Windows desktop at the location of a window without this window appearing in the screen shot.This example uses this tip to zoom the part of the screen found below the magnifier.